An ab Initio Molecular Orbital Study of the Hydrogen Sorbed Site in Co/MoS₂Catalysts

Abstract

A cluster model quantum chemical approach is used to study the electronic structure of Co in bimetallic sulfide catalysts Co/MoS2. The oxidative addition of hydrogen to the Co−Mo component is considered. Ab initio HF/MP2 and DFT calculations show that hydrogen occluded in the catalyst bulk is sorbed on the cobalt ion and stabilizes the Co(III) d6 electronic state of cobalt ions in the sulfide catalysts. This electronic state is rather active, when surface sites interact with the S-containing reagents participating in the HDS catalysis. A model of active sites on the Co/MoS2 catalyst is used to discuss the suggested molecular mechanism of the HDS catalysis.